Police officers direct the evacuation of attendees of the Muhammad Art Exhibit and Contest sponsored by the American Freedom Defense Initiative after a shooting outside the Curtis Culwell Center where the event was held in Garland, Texas May 3, 2015. REUTERS/Mike Stone

Citing a senior FBI official, ABC News on Monday identified one of the gunmen at Sunday’s attack at an exhibit of caricatures of the Prophet Mohammad in a Dallas suburb as Elton Simpson, an Arizona man previously the target of a terror investigation.

FBI agents and a bomb squad were searching Simpson’s Phoenix home overnight, ABC said. Garland, Texas police and the Federal Bureau of Investigation had no immediate comment on the report.